When performing computer-based modeling or generation of surfaces, it is important that light scattering be done in a way that resembles the natural reflection. The more realistic the light scattering, the more natural-looking and believable the image will be. One category of surfaces that have specific scattering properties are so-called translucent or transparent materials. These occur frequently in nature in a variety of contexts. Organic materials such as skin, liquids, and food items can have translucent properties, as can inorganic materials such as marble and other minerals, to name a few examples.
In some examples, translucency can occur in nature because the material at issue is multilayered. For example, skin is such a material, and photons that enter the outer surface of the skin can be subject to several scatterings therein. Sometimes the scattered photon is eventually absorbed inside the material or continues further into the underlying tissue, but there is a likelihood that at least some of the scattered photons will exit the multilayered skin structure through the outer surface where they entered. In so doing, some of the photons can emerge from the skin at locations other than their point of entry.